:root {
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;

  /* ===== 动效令牌 ===== */
  --motion-fast: 0.15s;
  --motion-base: 0.25s;
  --motion-slow: 0.4s;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
}

html { scroll-behavior: smooth; }

body { font-family: var(--font-sans); }

.font-serif { font-family: var(--font-serif); }
.font-sans { font-family: var(--font-sans); }

.markdown {
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.85;
  color: #111827;
  word-break: break-word;
}
.dark .markdown { color: #e2e8f0; }

.markdown h1 {
  font-size: 1.75em;
  font-weight: 700;
  color: #1e3a5f;
  border-bottom: 2px solid #b8860b;
  padding-bottom: .5em;
  margin: 1.2em 0 1em;
}
.dark .markdown h1 { color: #adc2d9; }

.markdown h2 {
  font-size: 1.3em;
  font-weight: 600;
  color: #1e3a5f;
  margin-top: 1.8em;
  margin-bottom: .8em;
  padding-left: .5em;
  border-left: 4px solid #b8860b;
}
.dark .markdown h2 { color: #d6e0eb; }

.markdown h3 {
  font-size: 1.1em;
  font-weight: 600;
  color: #3b5b7f;
  margin-top: 1.5em;
  margin-bottom: .6em;
}
.dark .markdown h3 { color: #84a3c7; }

.markdown h4 {
  font-size: 1em;
  font-weight: 600;
  color: #3b5b7f;
  margin-top: 1.2em;
  margin-bottom: .5em;
}
.dark .markdown h4 { color: #84a3c7; }

.markdown p {
  text-align: justify;
  text-justify: inter-ideograph;
  margin: 1em 0;
}

.markdown blockquote {
  border-left: 4px solid #b8860b;
  background: #f8f6f0;
  padding: 1em 1.5em;
  margin: 1.5em 0;
  color: #4b5563;
  border-radius: 0 8px 8px 0;
}
.dark .markdown blockquote {
  background: #1e293b;
  color: #cbd5e1;
}

.markdown table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
  font-size: .95em;
  display: block;
  overflow-x: auto;
}
.markdown th {
  background: #1e3a5f;
  color: #fff;
  padding: .75em 1em;
  text-align: left;
  font-weight: 600;
}
.dark .markdown th { background: #15293f; }
.markdown td {
  border-bottom: 1px solid #e2e8f0;
  padding: .75em 1em;
  color: #111827;
}
.dark .markdown td { border-bottom-color: #334155; color: #e2e8f0; }
.markdown tr:nth-child(even) td { background: #f8fafc; }
.dark .markdown tr:nth-child(even) td { background: #1e293b; }

.markdown code {
  background: #f1f5f9;
  padding: .15em .4em;
  border-radius: 4px;
  font-size: .9em;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  color: #b8860b;
}
.dark .markdown code { background: #0f172a; color: #d4a843; }

.markdown pre {
  background: #f8f6f0;
  color: #1e3a5f;
  padding: 1em 1.5em;
  border-radius: 8px;
  border-left: 4px solid #b8860b;
  border-top: 1px solid #ece7d6;
  border-right: 1px solid #ece7d6;
  border-bottom: 1px solid #ece7d6;
  overflow-x: auto;
  margin: 1.5em 0;
  box-shadow: 0 1px 2px rgba(184, 134, 11, .04);
}
.markdown pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  font-size: .92em;
}
.dark .markdown pre {
  background: #0f172a;
  color: #e2e8f0;
  border-left-color: #d4a843;
  border-top-color: #1e293b;
  border-right-color: #1e293b;
  border-bottom-color: #1e293b;
  box-shadow: none;
}

.markdown ul, .markdown ol {
  padding-left: 1.8em;
  margin: 1em 0;
}
.markdown li { margin: .5em 0; }

.markdown hr {
  border: none;
  border-top: 1px solid #b8860b;
  margin: 2em 0;
  opacity: .5;
}

.markdown a {
  color: #b8860b;
  text-decoration: underline;
  text-underline-offset: 2px;
}
.markdown a:hover { color: #d4a843; }

.markdown strong { font-weight: 700; color: #1e3a5f; }
.dark .markdown strong { color: #d6e0eb; }

.markdown img { max-width: 100%; border-radius: 8px; margin: 1em 0; }

.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  background: linear-gradient(90deg, #b8860b, #d4a843);
  z-index: 60;
  transition: none;
}

.sidebar-link {
  display: flex;
  align-items: baseline;
  gap: .45rem;
  width: 100%;
  padding: .45rem .75rem;
  border-radius: 6px;
  font-size: .84rem;
  line-height: 1.5;
  text-align: left;
  color: #4b5563;
  transition: background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out);
  cursor: pointer;
}
.sidebar-link .chapter-title {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.sidebar-link:hover { background: #f1f5f9; color: #1e3a5f; }
.dark .sidebar-link { color: #9a9a9a; }
.dark .sidebar-link:hover { background: #1e293b; color: #d6e0eb; }
.sidebar-link.active {
  background: rgba(184,134,11,.08);
  color: #1e3a5f;
  font-weight: 600;
  box-shadow: inset 3px 0 0 #b8860b;
}
.dark .sidebar-link.active {
  background: rgba(212,168,67,.12);
  color: #d6e0eb;
  box-shadow: inset 3px 0 0 #d4a843;
}

.card {
  background: #fff;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,.05);
  transition: box-shadow var(--motion-fast) var(--ease-out);
}
.card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
}
.card-interactive {
  cursor: pointer;
  transition: box-shadow var(--motion-fast) var(--ease-out), transform var(--motion-fast) var(--ease-out);
}
.card-interactive:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,.08);
  transform: translateY(-2px);
}
.dark .card {
  background: #1e293b;
  border-color: #334155;
}

.quote-card {
  border-left: 4px solid #b8860b;
  background: #f8f6f0;
  transition: border-color var(--motion-fast) var(--ease-out), background var(--motion-fast) var(--ease-out);
}
.quote-card:hover {
  border-left-color: #d4a843;
  background: #faf7ef;
}
.dark .quote-card { background: #1e293b; }
.dark .quote-card:hover { background: #223047; }

.fade-enter { animation: fadeIn var(--motion-base) var(--ease-out); }
.chapter-enter { animation: fadeUp var(--motion-slow) var(--ease-out); }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; }
}

/* ===== 滚动 reveal ===== */
.reveal { opacity: 0; }
.reveal.reveal-visible {
  opacity: 1;
  animation: fadeUp var(--motion-slow) var(--ease-out) both;
}
.reveal-group > * { opacity: 0; }
.reveal-group.reveal-visible > * {
  animation: fadeUp var(--motion-slow) var(--ease-out) both;
}
.reveal-group.reveal-visible > *:nth-child(2) { animation-delay: 60ms; }
.reveal-group.reveal-visible > *:nth-child(3) { animation-delay: 120ms; }
.reveal-group.reveal-visible > *:nth-child(4) { animation-delay: 180ms; }
.reveal-group.reveal-visible > *:nth-child(5) { animation-delay: 240ms; }
.reveal-group.reveal-visible > *:nth-child(n+6) { animation-delay: 300ms; }

@media (max-width: 768px) {

  .markdown h1 { font-size: 1.5em; }
  .markdown h2 { font-size: 1.2em; }
}

.btn-primary {
  background: #1e3a5f;
  color: #fff;
  padding: .75rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  transition: background var(--motion-fast) var(--ease-out), transform var(--motion-fast) var(--ease-out);
  cursor: pointer;
  display: inline-block;
}
.btn-primary:hover { background: #15293f; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0) scale(.98); transition-duration: .05s; }
.dark .btn-primary { background: #b8860b; color: #0f172a; }
.dark .btn-primary:hover { background: #d4a843; }
.dark .btn-primary:active { transform: translateY(0) scale(.98); }


.btn-secondary {
  background: transparent;
  color: #1e3a5f;
  border: 2px solid #1e3a5f;
  padding: .75rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  transition: background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out), transform var(--motion-fast) var(--ease-out);
  cursor: pointer;
  display: inline-block;
}
.btn-secondary:hover { background: #1e3a5f; color: #fff; }
.btn-secondary:active { transform: scale(.98); transition-duration: .05s; }
.dark .btn-secondary { color: #adc2d9; border-color: #adc2d9; }
.dark .btn-secondary:hover { background: #adc2d9; color: #0f172a; }

.icon-btn {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  cursor: pointer;
  transition: background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out), transform var(--motion-fast) var(--ease-out);
  color: #4b5563;
}
.icon-btn:hover { background: #f1f5f9; color: #1e3a5f; }
.icon-btn:active { transform: scale(.92); transition-duration: .05s; }
.icon-btn:disabled { opacity: .35; cursor: default; }
.icon-btn:disabled:hover { background: transparent; }
.dark .icon-btn { color: #9a9a9a; }
.dark .icon-btn:hover { background: #1e293b; color: #d6e0eb; }

/* ===== 阅读顶栏"更多"菜单（移动端折叠） ===== */
.menu-item {
  display: flex;
  align-items: center;
  gap: .5rem;
  width: 100%;
  padding: .5rem .75rem;
  border-radius: 8px;
  font-size: .875rem;
  color: #4b5563;
  text-align: left;
  transition: background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out);
  cursor: pointer;
}
.menu-item:hover { background: #f1f5f9; color: #1e3a5f; }
.dark .menu-item { color: #9a9a9a; }
.dark .menu-item:hover { background: #1e293b; color: #d6e0eb; }

/* ===== 作者区：迷你书卡 / 联系胶囊 / 头像 ===== */
.book-card {
  display: flex;
  align-items: center;
  gap: .625rem;
  padding: .625rem .75rem;
  border: 1px solid #e2e8f0;
  border-radius: 10px;
  background: #fff;
  transition: transform var(--motion-fast) var(--ease-out), box-shadow var(--motion-fast) var(--ease-out), border-color var(--motion-fast) var(--ease-out), background var(--motion-fast) var(--ease-out);
}
.book-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(15,31,48,.08);
  border-color: rgba(184,134,11,.4);
  background: #fdfbf5;
}
.dark .book-card { border-color: #334155; background: rgba(30,41,59,.5); }
.dark .book-card:hover {
  border-color: rgba(212,168,67,.45);
  background: #1e293b;
  box-shadow: 0 4px 12px rgba(0,0,0,.35);
}
.book-card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: #ebf0f5;
  color: #1e3a5f;
  transition: background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out);
}
.book-card:hover .book-card-icon { background: #b8860b; color: #fff; }
.dark .book-card-icon { background: #0a1521; color: #adc2d9; }
.dark .book-card:hover .book-card-icon { background: #d4a843; color: #0f172a; }
.book-card-arrow {
  flex-shrink: 0;
  color: #94a3b8;
  transition: color var(--motion-fast) var(--ease-out), transform var(--motion-fast) var(--ease-out);
}
.book-card:hover .book-card-arrow { color: #8b6508; transform: translate(2px, -2px); }
.dark .book-card:hover .book-card-arrow { color: #d4a843; }

.contact-chip {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .4rem .75rem;
  border: 1px solid #e2e8f0;
  border-radius: 999px;
  font-family: inherit;
  font-size: .75rem;
  color: #4b5563;
  background: #fff;
  cursor: pointer;
  transition: transform var(--motion-fast) var(--ease-out), border-color var(--motion-fast) var(--ease-out), background var(--motion-fast) var(--ease-out), color var(--motion-fast) var(--ease-out));
}
.contact-chip:hover {
  transform: translateY(-1px);
  border-color: rgba(184,134,11,.5);
  background: rgba(184,134,11,.05);
  color: #8b6508;
}
.dark .contact-chip { border-color: #334155; color: #9a9a9a; background: rgba(30,41,59,.5); }
.dark .contact-chip:hover { border-color: rgba(212,168,67,.5); background: rgba(212,168,67,.08); color: #d4a843; }
.contact-chip svg { color: #1e3a5f; transition: color var(--motion-fast) var(--ease-out); }
.contact-chip:hover svg { color: #8b6508; }
.dark .contact-chip svg { color: #adc2d9; }
.dark .contact-chip:hover svg { color: #d4a843; }

.author-avatar {
  transition: transform var(--motion-base) var(--ease-out), box-shadow var(--motion-base) var(--ease-out);
}
.author-avatar:hover {
  transform: scale(1.04);
}

/* ===== 键盘 focus-visible 焦点环（可访问性） ===== */
.book-card:focus-visible,
.contact-chip:focus-visible {
  outline: 2px solid #b8860b;
  outline-offset: 2px;
}
.dark .book-card:focus-visible,
.dark .contact-chip:focus-visible {
  outline-color: #d4a843;
}

/* ===== 品牌 loading spinner ===== */
.brand-spinner {
  display: inline-block;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 3px solid rgba(184,134,11,.25);
  border-top-color: #b8860b;
  animation: spin .8s linear infinite;
}
.dark .brand-spinner { border-color: rgba(212,168,67,.2); border-top-color: #d4a843; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== 沉浸式阅读模式 ===== */
/* v2.0：顶栏固定常驻，沉浸时不隐藏；聚焦靠阅读宽度收窄 + 侧栏收起 */

/* 桌面侧边目录：沉浸时滑出隐藏，点击顶栏目录按钮唤出（.sidebar-show） */
.read-sidebar { transition: transform var(--motion-base) var(--ease-out); }
.immersive .read-sidebar {
  transform: translateX(-105%);
  transition-delay: 100ms;
}
.immersive .read-sidebar.sidebar-show {
  transform: translateX(0);
  transition-delay: 0ms;
}

/* 阅读区：沉浸时取消侧栏留白、宽度收窄聚焦 */
.immersive .read-main { margin-left: 0 !important; }

.read-article { transition: max-width var(--motion-slow) var(--ease-in-out); }
.immersive .read-article {
  max-width: 680px;
  transition-delay: 200ms;
}
/* 沉浸时行距舒展、字距微调（覆盖 inline style 需 !important） */
.immersive .markdown {
  line-height: 1.9 !important;
  letter-spacing: .01em;
}

/* 翻页卡片：沉浸时淡出（提升可见性 0.15→0.35），悬停恢复；上方加 Gold 渐变暗示线 */
.chapter-nav { transition: opacity var(--motion-base) var(--ease-out); }
.immersive .chapter-nav { opacity: .35; }
.immersive .chapter-nav:hover { opacity: 1; }
.immersive .chapter-nav::before {
  content: "";
  display: block;
  height: 1px;
  margin: -6px 0 18px;
  background: linear-gradient(90deg, transparent, #b8860b, transparent);
  opacity: .6;
}

/* 进度条：沉浸时更细 */
.immersive .reading-progress { height: 2px; }


/* ===== 可访问性：减弱动态效果兜底 ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }
  .reveal,
  .reveal-group > * { opacity: 1 !important; }
}